Left to Right Shunt Study. Normal Value.
The normal value for the radionuclide technique is as follows:
Qp:Qs = < 1,2
The method of Maltz and Treves, calculates the lung and systemic flow using the area under the lung (A1) and early recirculation (A2) time activity curves. If A2=0, no shunt, then Qp:Qs= 1. Normally there is recirculation of the bronchial vessels, so the normal figure is up to 1.2.
A1/A1-A2
References:
1 Peix A. Medicina Nuclear en Cardiología Pediátrica, p 151-158 in: Medicina Nuclear Aplicaciones Clínicas. Eds: I. Carrio - P. González. Editorial Masson, Barcelona España, 2003.
2 Maltz DL, Treves S. Quantitative radionuclide angiocardiography: determination of Qp: Qs in children. Circulation. 1973 May;47(5):1049-56.